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<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>

<body>
    <script>
        class Father {
            say() {
                return '我是爸爸'
            }
        }
        class Son extends Father{
            say() {
                console.log(super.say()+'的儿子');
                
            }
        }
        var son = new Son();
        son.say();
    </script>
</body>

</html>